Sorry if this question is in the wrong place. But I have a hp desktop that is about 3 yrs old and about 2 months ago i started to notice that the fan in the pc gets louder and louder than it slows down almost instantly then back up to full speed again minutes later. It does this all the time. It is really annoying. Speeds up slows down speeds up slows down. It has never done this before at least not that I could hear or notice it. How could I quit it down. Maybe a new quiter fan or something. I have no idea what to do. I have been using my laptop more lately cause it is that annoying. Any help here would be appreciated, Thanks

You system might be running hot and be in need of a good cleaning. As the system gets warm, the fan speed increases. The increased airflow cools the system which then reduces the fan speed. If the system has been running warm for extended periods of time, it may have caused the thermal grease between the CPU & heatsink to dry out. In that case, remove heatsink, clean off old thermal grease, apply thin layer of new grease, reinstall heatsink.